This is a Phase II open-label study in approximately 200, and up to 240, healthy males and non-pregnant females, aged 18 years and older. This study is designed to assess the safety, reactogenicity, and immunogenicity of an unadjuvanted subvirion monovalent inactivated influenza H3N2v vaccine manufactured by Sanofi Pasteur. Subjects will be stratified by age (approximately 100 (up to 120) subjects 18-64 years old and approximately 100 (up to 120) subjects >/= 65 years old) to receive two doses of vaccine, delivered intramuscularly as 15mcg HA/0.5mL dose, 21 days apart. The duration of the study for each subject will be approximately 7 months.